diff --git a/clang-tools-extra/clangd/Selection.cpp b/clang-tools-extra/clangd/Selection.cpp
--- a/clang-tools-extra/clangd/Selection.cpp
+++ b/clang-tools-extra/clangd/Selection.cpp
@@ -501,7 +501,7 @@
   //  - those without source range information, we don't record those
   //  - those that can't be stored in DynTypedNode.
   bool TraverseDecl(Decl *X) {
-    if (X && isa<TranslationUnitDecl>(X))
+    if (isa_and_nonnull<TranslationUnitDecl>(X))
       return Base::TraverseDecl(X); // Already pushed by constructor.
     // Base::TraverseDecl will suppress children, but not this node itself.
     if (X && X->isImplicit())